Publications (Paul's Blog)

December 18, 2009

EXOTIC INVADER OR EXCELLENT LAWNGRASS?

Filed under: Uncategorized — Paul Dowlearn @ 7:48 pm

Bermuda grass (cynodon dactylon) is the most widely used lawn grass in Texas. It is also very popular among farmers and ranchers and has been planted extensively as a reliable forage or hay crop. Despite this, it is also listed as being among the top three most invasive plants in our state.
Evidence of this opposing view regarding bermuda grass is apparent on the Texas A&M website. Page after page will extol the virtues of this lawn grass. Every aspect from mowing, watering, and fertilization to disease or insect problem solving is covered. In addition, you will find a bewildering amount of seed or sod cultivars to choose from. After viewing this huge body of information, click over to the section on invasive species to find page after page on bermuda grass prevention and eradication. Enough to cause major concern for any home owner bent on growing a nice looking lawn.
Bermuda grass is in fact listed as an exotic invader on almost every invasive plant species list across the continent. The strict definition of invasive is any plant that escapes cultivation to compete with local natives or plants grown for agricultural use. This is done mainly by seed, rhizomes (root runners), or stolons (above ground runners). Bermuda grass is capable of propagating itself by all three mechanisms.
My wife Nila and I came across a stand of wild bermuda growing in a road ditch while field tripping the Chihuahuan Desert in far West Texas. This is the driest environment in the state averaging 6 to 8 inches of rain (sometimes much less) per year. Yet here bermuda was found making a home for itself in the lower parts of the ditch. My comment was, “If it can survive out here we probably will never be able to get rid of it.”
Eradication of bermuda is basically impossible on a large scale but can be managed on small plots. Methods range from smothering using landscape fabrics, plastic, layering newspaper or cardboard, to physical removal, and/or resorting to various chemical applications. All of these methods work to some degree but none are 100% effective. Total eradication comes only through diligence and repeated effort regardless of which method or combination of tactics you may choose.
Generally, our landscape crew will opt for physical removal as this time tested method works as well as any and is the fastest way to transform lawn into garden. Bear in mind that this is also the most labor intensive as it entails removing entirely the top 3” or 4” of soil. After replacing with clean topsoil you will invariably find a few sprigs that managed to escape your first effort. These can normally be dug out easily enough if dealt with in an expedient manner. If you attempt to shake or screen out roots and stolons in an effort to preserve existing topsoil, you need to be keenly aware that any part of this grass you leave behind can regenerate. A small tractor or skid steer loader can come in mighty handy for larger areas.
The hardest bermuda cultivars to eradicate are the ones used in agriculture for forage and hay. These super aggressive and larger growing bermudas can often taint an otherwise pristine building site by being brought in with fill dirt or topsoil. Try as they might to screen or maintain a watchful eye, folks in the dirt hauling business have a really hard time managing this when dealing with ton after ton of soil. With more and more people building country homes and guys like myself being hired to provide landscapes using native grasses and ornamentals, we find unwanted bermuda coming in on contracted fill dirt to be quite common. Our first task then is to eradicate this foreign invader before we can begin our work. Once established, a stand of coastal bermuda is basically impossible to totally eradicate. In this case, an ounce of prevention is worth a ton of cure. Literally…..
All this being said, if you are intent on planting a bermuda lawn, you should know that bermuda grass is ranked third place in terms of water requirements and maintenance. Buffalo grass and zoysia cultivars are respectively ranked first and second when it comes to mowing, watering, and fertilizing. However, as stated earlier, bermuda remains popular among homeowners and those maintaining golf courses or athletic fields.

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